class Group:
    def __init__(self, group_name, company_name, staffs):
        self.group_name = group_name
        self.company_name = company_name
        self.staffs = staffs

    def __getitem__(self, item):
        return self.staffs[item]

    def __reversed__(self):
        pass

    def __len__(self):
        pass

    def __iter__(self):
        pass

    def __contains__(self, item):
        pass


if __name__ == '__main__':
    test = Group(group_name="ceshi", company_name="xinmingzhu", staffs=["leo", "tom", "ken", "joe"])
    a = test[:3]
    print(a)